Telephone system



July 29, 1930. w. SCHULZ TELEPHONE SYSTEM Filed Sept. 15, 1926 mmijm 1fimma- Mernar Schulz Patented July 29, 1930 UNITED STATES PATEN'ro FicE WERNER SCHULZ, 0F BERLIN, GERMANY, ASSIGNOR T0 SIEMENS & HALSKE AKTIEN- GESELLSGHAFT, WEBNERWERK, 0F SIEMENSS'IADT, NEAR BEBLDN', GEBKANY rnnnrnoun sxsrnm Application filed September 15, 1926, Serial No. 135,531, and in Germany September 26, 1925.

In telephone exchanges with which appli cant is familiar hitherto all the trafiic has passed over trunk positions, which were provided for this purpose with a trunk multiple field. To render the trafiic more easily su ervised and concentrated, it is proposed t at, in future the through going calls are to pass over separate positions (switching through positions). The supervision of the conversation, however, is to remain at the trunk positions; hence it is better if the supervisory signals, hitherto used at the trunk positions, can be retained without any alteration or addition.

According to the invention, the new circuit of the' switching through position with amplifiers is so arranged that no addition need e made at the existing position.

The drawing shows by way of example one method of arranging the circuit. The manner in which the traffic isdealt with will now be explained.

While the plugs FVS 1 and FVS 2 of the double cord circuit with amplifiers are in the multiple jacks of the existing trunk lines, such as FLTG 2 the plugs FS 1 and FS 2 of the cord circuit where supervision takes place are inserted in the jacks K'va 1 and Koa 2, thus connecting the plugs to the amplifier circuit in accordance with the invention. In known manner the amplifier is provided with relays-RR 1 and RR 2, which are operated by ringing current received over the trunk line.

These relays enable the call to be sent into the other trunk line by energizing the ringing current re-transmitting relays WK 1 and WK 2, they also enable signals to be sent to the trunk position by connecting up additional relays (FLR 1 and FLR 2).

If the trunk operator wishesto have a connection set up over amplifiers between two trunk lines, she communicates over an order wire with the switching through operators position with amplifiers, and causes the switching through operator to connect at the multiple jacks her own trunk line to the wanted trunk line. The switching through operator gives the trunk operator the number 0? the amplifier cord circuit. The trunk oper- C3 ator then inserts the plug FS 2 of the trunk cord circuit into the jack Koa 2, which is provided at all the trunk positions and is associated with the amplifier cord circuit. The following circuit is thus established 1. Earth, battery, relay FHR 2, plug FS 2, jack Km 2, c-lead back contact pr 21, winding II of relay FLR 2, interrupter U, earth.

The interrupterU causes the relay FLR 2 to be operated in series with FHR 2, the lamp PL is flashed over the contact fir-21 as folows: V

2. Earth, front contact'flr 21, back contact er 23, lamp UL, battery, earth.

The relay FLR 2 also transmits current impulses over the a and 7) leads to the'relay FSR 2 in the trunk cord circuit:

3. Earth, battery, winding III of relay PR 2, front contact flr 25, a-lead, jack Km 2, plug FS 2, key FRU 21, relay FSR 2 windmg I, key FRU 22, plug FS 2, jack Kva 2, b-lead, front contact flr 24, earth.

The supervisory lamp FSL 2 in the trunk cord circuit is flashed over:

Earth, front contact fsr 2, winding II of relay FS R 2, front contact fhr 21, lamp FSL 2, battery, earth.

The switching through operator now inserts the plug FVS 2 into the multiple jack FKV 2 of the wanted trunk line and she inserts the plug FVS 1 into the multiple jack FKV 1 of the calling trunk line. If the wanted trunk line be engaged, the relay PR 2 in the switching through cord circuit cannot operate, hence the supervisory lamp UL at the switching through position and, the lamp FSL 2 atthe trunk position continue to flash. When the wanted line becomes free, the relay PR 2 is operated over:

6. Earth, battery, winding I of relay FLR nects the supervisory lamp UL at the switch ing through position,'at its contact zr 21 it opens the circuit for energizing relay FLR 2 and it looks itself over its own contact er 22.

' When the relay FLR 2 operated, it energized the relay FSR 2 at the trunk posifion (circuit 3) and the latter locks itself (circuit 4), because relay FI-IR 2 remains attracted. The

, supervisory lamp FSL 2 at the trunk position burns steadily to indicate that the wanted trunk line has become free. The trunk operator can now effect the switching over of her line in themultiple field at the amplifier position. She inserts the plug FS 1 belonging to the plug FS 2, which is in the jack Koa 2, into the jack Koa 1 associated with the amplifier cord circuit:

8. 1, jack Kva 1, c-lead, back contact pr 11, winding II of relay FLR 1, interrupter U 1. earth.

The supervisory lamp FSL 1 now flashes in the same way as previously did the lamp FSL 2. If the trunk operator has released by withdrawing the plu from the answering jack of the trunk line FIlOt shown in the drawmg) the relay PR 1 at the switching through position with amplifier can then operate as follows:

9. Earth, c-lead, jack Fk'v 1, winding II and I of relay PR 1, battery, earth.

The relay PR 1 is energized and over its contacts the following circuits are established:

10. Earth,battery, winding I of relay FLR 1, frontcontact pr 12, back contact er 11, earth.

The relay FLR 1 is operated and its contacts fl'r 14 and 15 close a circuit for the relay FSR 1:

11: Earth, battery, winding III of relay PR 1, front contact flr 15, b-lead, jack Kva 1, lugs FS 1, key 'FRU 12, winding I of relay SR 1, key FRU 11, plug FS 1, jack Ken 1, (i-lead, front contact flr 14, earth.

The relays DR 1 and ZR 1 are now operated over the contact flr 11 12. Earth, battery, relay FHR 1, plug FS 1, jack K'va 1, c-lead, front contact pr 13, relays DR 1 and ZR 1, front contact flr' 11, earth.

The relays DR 1, ZR 1 and FSR 1 are energized, hence the lamp FSL 1 burns steadily. At the amplifier, the lighting relay ZR 3 is energized over the contacts 21" 14 and zr 24: 13. Earth, battery, resistance SW 10, front contacts 2r 14 and 27' 24, relay ZR 3, earth.

Earth, battery, relay FRH 1, plug FS" The amplifier lamps are now lighted. The plugs FVS 1 and FVS 2 have been switched through to the amplifier over the contacts air 11, 12, 13 and do" 21, 22, 23. If the operator wants to call the end stations, she actuates in known manner her ringing key FRU 11, 12 or'FRU 21, 22:

14. Source of alternating current, key FRU 11, plug FS 1, jack Koa l, a-lead, bac contact fZr 12. relay AR 1, back contact fl? 13, b-lead, jack Kim 1, plugs FS 1, key FRU 12, source of alternating current.

Thereby the relays AR 1 or AR 2 are energized in the switching through cord circuit, and they energize the call transmitting relays WR 1 or WR 2.

15. Earth, battery, call transmitting relay \VR 1, front contact a? 11, earth.

These relays over their contacts wr 11, 12 and 101' 21, 22 send ringing currents to the particular trunk line. The ringing current arriving over the trunk line Flt'g 1 operates the relay RR 1. This at its contact W 11 operates the relay WR 2 in'series with the relay HR 1.

16. Earth, battery, relay WR 2, front contact 1'1' 11, relay HR 1, earth.

The relay WR 2 is operated, hence ringing current flows over its contacts wr 21, 22 in the other trunk line Fltg 2. The relay HR 1 energizes the relay FLR 1 over:

17. Earth. front contact hr 11, winding I of relay FLR 1, battery, earth, so that the relay FSR 1 in the trunk cord circuit is operated over the contacts fZr 12, 13.

The relay F SR 1 locks itself over: 18. Earth. front contact far 1, winding II of relay FSR 1, front contact fhr 11, lamp 'FSL 1, battery, earth.

The lamp FLS 1 burns steadily. In the same manner the lamp FSL 2 is lighted when ringing current arrives over the trunk line Fltg 2. At the end of the conversation, when the trunk operator releases the connection by withdrawing the plugs FS 1 and FS 2 from the jacks Kva 1 and Kva 2, the relays DR 1, ZR 1, DR 2, ZR 2 are deenergized. The amplifier is extinguished; the plugs are disconnected from the amplifier; the relay FLR 2 is again energized (circuit 6), and the supervisory lamp UL is lighted at the switchin through position:

19. Earth, front contact flr 21, back contact 27 23, lamp UL, battery, earth.

The lamp UL is extinguished when the plugs of the amplifier cord circuit are withilrawn from the multiple jack of the trunk What is claimed is: I

1. In a telephone system, a trunking operators position, a cord circuit at said position for extending calls, two trunk lines, means including said cord circuit for connecting said trunk lines together, a switching through operators position, an amplifying cord circuit at said second position, amplifying means in said cord circuit normally inoperative, means including said amplifying cord circuit for connecting said trunk lines together, terminals individual to said amphfying cord circuit at said first position, and

means responsive to the connection of a trunking cord circuit with said terminals for rendering said amplifying means operative.

2. In a telephone system, a switching through operators position, an amplifying cordcircuit at said position, two trunk lines, means including said cord circuit for connecting said trunk lines together, a trunking o erators osition terminals individual to said amplifying cord circuit terminating at said trunking operators position, a cord circuit at said trunking operators position'for connecting with said terminals, and means in said trunking cord circuit for supervising the connection.

3. In a telephone system, a switching connecting said trunk lines by way of saidamplifying cord circuit and for connecting said trunking operators cord circuit to said amplifying cord circuit whereby said trunking operators cord circuit is usedfor super- 86 visorv purposes.

4. n a telephone system, a switching through operators position, an amplifying cord circuit at said position, trunk lines, ter

minals for connecting two of said trunk lines over said cord circuit, a trunking operators position, a cord circuit at said trunking position and means for connecting said last men tioned cord with said amplifying cord circuit for supervisory purposes.

5. In a telephone system, an operators position, a cord circuit at said position for extending calls, a second operators position, an amplifying cord circuit at said second position, means for establishing a connection over said amplifying cord circuit, and branch connections extending from said amplifying cord circuit to said first position for connecting said first cord circuit with said amplifying cord circuit in such a manner that the first cord circuit is used for supervisory purposes,

6. In a telephone system, a plurality'of circuits any one of which maybe used trunks, amplifying and non-amplifying cord to the exclusion of the others as a link interconnecting two trunks, supervisory means associated with said non-amplifying cords, a branch from each amplifying cord terminating in a jack, and means responsive to the insertion of a plug of a non-amplifymg through operators position,

interconnecting tiple connections from said amplifying cord cord into the jack of anamplifyin cord for rendering the supervisory means 0 the associated non-amplifying-cord effective to indicate conditions of connections over the associated amplifying cord. 7

, 7. In a telephone system, a plurality of trunks, amplifying and non-amplifying cord circuits anyone of which may be used to the exclusion of the others as a link interconnecting two trunks, supervisory means associated with said non-amplifying cords, two branches from each amplifying cord terminating in jacks, and means responsive to the interconnection of the two jacks of any amplifying cord by a non-amplifying cord for rendering the supervisory means of the associated non-amplifying cord effective to indicate conditions of connections over the associated amplifying cord.

8. In a telephone system, a cord circuit including normally inoperative amplifying means, means for connecting said cord circuit as a link in a telephone connection, a branch extending from said cord circuit and terminating in a jack, and means responsive to the extension of a connection. to said branch by way of said jack for rendering said amplifying means effective.

9. In a telephone system, a plurality of trunking operators positions, a switchingtrunk lines multiple connected to jacks at each of ,said first mentioned positions and at said second mentioned position, cord circuits at each of said first positions for interconnecting said trunk lines, amplifying cord circuits at said switching-through operators position for said trunk lines, and mulextending to each of said first mentioned operators positions. a

10. In a telephonesystem, a plurality of trunking operators positions, a switchingthrough operators position, trunk lines multiple connected to jacks at each of said first mentioned positions and at said second position, cord circuits at each of said first ositions for interconnectingsaid trunk mes, an amplifying cord circuit at said switching-through operators position for interconnecting said trunk lines, multiple connections from said amplifying cord extending to each of said first mentioned operatorls positions, and means at each of said first mentioned operators positions each controlled over one of said cords at said trunking operators position for supervising connections over the amplifying cord.

11. In a telephone system, a plurality of trunk lines, a link circuit for establishing a connection between two of saidtrunk lines, a branch from said link circuit, a source of characteristic current, andme'ans in said link circuit, when a connection between two trunk lines is established as set forth,- n'sive to a signal current applied to one of t e cong nected trunk lines or to said branch for coni ecting said current source to the other trunk v me. 12. In atelephone system, a plurality of trunk lines, a hnk circuit for establishing a connection between two of said trunk lines, two branches from said link circuit, a source 1 of characteristic current, means in said link circuit controlled over one or the other of j said branches for connecting said current source to one or the other of said trunk lines I connected as set forth, "and means responsive 1;,- to the application of a signal current to either trunk line for reconnecting said ourrent source to the other trunk 11116.

13. Inatelephone system, a plurali of trunk lines, a first link-circuit, a second an circuit, meansincluding either one of said link circuits for connecting said'trunk linestogether, two branches from said first link circuit, and means for connecting said secv 0nd link circuit to said branches for super- 26 visory purposes when said first link circuit 'is used for establishing a connection as set forth. In witness whereof, I hereunto subscribe in name this 21st da of Au A. D. 1926. "as y witnsi ii cnunz. 

